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Articles 1 - 30 of 441
Full-Text Articles in Geology
Post-Wildfire Recovery Of An Upland Oak-Pine Forest On The Cumberland Plateau, Kentucky, Usa, Devin E. Black, Zachary W. Poynter, Claudia A. Cotton, Suraj Upadhaya, David D. Taylor, Wendy Leuenberger, Beth A. Blankenship, Mary A. Arthur
Post-Wildfire Recovery Of An Upland Oak-Pine Forest On The Cumberland Plateau, Kentucky, Usa, Devin E. Black, Zachary W. Poynter, Claudia A. Cotton, Suraj Upadhaya, David D. Taylor, Wendy Leuenberger, Beth A. Blankenship, Mary A. Arthur
Forestry and Natural Resources Faculty Publications
Background: Many forests within the southern Appalachian region, USA, have experienced decades of fire exclusion, contributing to regeneration challenges for species such as oaks (Quercus spp. L.) and pines (Pinus spp. L.), and threatening the maintenance of oak-dominated forests in the future. While the use of prescribed fire as a forest management tool is increasing within this region, there remains a lack of information on the potential role of wildfire. A wildfire within the Daniel Boone National Forest, Kentucky, USA, provided an opportunity to investigate how wildfire affected forest vegetation response.
Results: We examined the effects of fire …
Groundwater Level Response To The Wenchuan Earthquake Of May 2008, Anhua He, Ramesh Singh
Groundwater Level Response To The Wenchuan Earthquake Of May 2008, Anhua He, Ramesh Singh
Mathematics, Physics, and Computer Science Faculty Articles and Research
We have comprehensively analysed the co-seismic response of the groundwater levels of 280 wells in mainland China that were associated with the Wenchuan earthquake (Mw 7.9) that occurred on 12 May 2008. The observed co-seismic responses can be classified as step-like changes in 138 wells, variations in 69 wells and non-responses in 73 wells. After a quantitative analysis of spatial distribution, there was no spatially coherent signal found in the step-like changes (positive values indicate a step-like rise, and negative values indicate a step-like fall), even within 300 km of the epicenter. The amplitude and the phase shift of the …
Climate Evolution Across The Mid-Brunhes Transition, Aaron M. Barth, Peter U. Clark, Nicholas S. Bill, Feng He, Nicklas G. Pisias
Climate Evolution Across The Mid-Brunhes Transition, Aaron M. Barth, Peter U. Clark, Nicholas S. Bill, Feng He, Nicklas G. Pisias
School of Earth & Environment Departmental Research
The Mid-Brunhes Transition (MBT) began ∼ 430 ka with an increase in the amplitude of the 100 kyr climate cycles of the past 800 000 years. The MBT has been identified in ice-core records, which indicate interglaciations became warmer with higher atmospheric CO2 levels after the MBT, and benthic oxygen isotope (δ18O) records, which suggest that post-MBT interglaciations had higher sea levels and warmer temperatures than pre-MBT interglaciations. It remains unclear, however, whether the MBT was a globally synchronous phenomenon that included other components of the climate system. Here, we further characterize changes in the climate system across the MBT …
Geomorphology Of Shell Ridges And Their Effect On The Stabilization Of The Biloxi Marsh, East Louisiana, Frances R. Crawford
Geomorphology Of Shell Ridges And Their Effect On The Stabilization Of The Biloxi Marsh, East Louisiana, Frances R. Crawford
LSU New Orleans Theses and Dissertations
Extensive shell ridges frame the edges of marsh platforms in parts of the Biloxi Marsh of southeast Louisiana. The exact sources of the shells in these accumulations have not been clearly identified but the most likely source is a combination of shells from modern offshore and shells excavated from buried St. Bernard delta deposits. Larger or fetch-protected ridges remain stable through time, whereas ridges facing open water are more mobile, moving as much as 38 m inland from July 2017 to January 2018. Behind stable ridges, marsh platform biomass is relatively unaffected. When ridges are mobile, vegetation is smothered, leaving …
The Relationship Between The Phosphate And Structural Carbonate Fractionation Of Fallow Deer Bioapatite In Tooth Enamel, Holly Miller, Carolyn Chenery, Angela L. Lamb, Hilary Sloane, Ruth F. Carden, Levent Atici, Naomi Sykes
The Relationship Between The Phosphate And Structural Carbonate Fractionation Of Fallow Deer Bioapatite In Tooth Enamel, Holly Miller, Carolyn Chenery, Angela L. Lamb, Hilary Sloane, Ruth F. Carden, Levent Atici, Naomi Sykes
Anthropology Faculty Research
Rationale The species‐specific relationship between phosphate (δ18OP values) and structural carbonate (δ18OC values) oxygen isotope ratios has been established for several modern and fossil animal species but until now it has not been investigated in European fallow deer (Dama dama dama). This study describes the relationship between phosphate and structural carbonate bioapatite in tooth enamel of extant fallow deer, which will help us further understand the species' unique environmental and cultural history. Methods The oxygen isotope composition of phosphate (δ18OP value) and structural carbonate (δ18OC value) of hydroxylapatite was determined in 51 modern fallow deer tooth enamel samples from across …
Magmatic Response To Subduction Initiation: Part 1. Fore-Arc Basalts Of The Izu-Bonin Arc From Iodp Expedition 352, John W. Shervais, Mark Reagan, Emily A. Haugen, Renat R. Almeev, Julian A. Pearce, Julie Prytulak, Jeffrey G. Ryan, Scott A. Whattam, Marguerite Godard, Timothy Chapman, Hongyan Li, Walter Kurz, Wendy R. Nelson, Daniel Heaton, Maria Kirchenbaur, Kenji Shimizu, Tetsuya Sakuyama, Yibing Li, Scott K. Vetter
Magmatic Response To Subduction Initiation: Part 1. Fore-Arc Basalts Of The Izu-Bonin Arc From Iodp Expedition 352, John W. Shervais, Mark Reagan, Emily A. Haugen, Renat R. Almeev, Julian A. Pearce, Julie Prytulak, Jeffrey G. Ryan, Scott A. Whattam, Marguerite Godard, Timothy Chapman, Hongyan Li, Walter Kurz, Wendy R. Nelson, Daniel Heaton, Maria Kirchenbaur, Kenji Shimizu, Tetsuya Sakuyama, Yibing Li, Scott K. Vetter
Geosciences Faculty Publications
The Izu-Bonin-Mariana (IBM) fore arc preserves igneous rock assemblages that formed during subduction initiation circa 52 Ma. International Ocean Discovery Program (IODP) Expedition 352 cored four sites in the fore arc near the Ogasawara Plateau in order to document the magmatic response to subduction initiation and the physical, petrologic, and chemical stratigraphy of a nascent subduction zone. Two of these sites (U1440 and U1441) are underlain by fore-arc basalt (FAB). FABs have mid-ocean ridge basalt (MORB)-like compositions, however, FAB are consistently lower in the high-field strength elements (TiO2, P2O5, Zr) and Ni compared to MORB, with Na2O at the low …
Petrogenesis Of Enriched And Intermediate Poikilitic Shergottites: From Magmatic Source To Emplacement, Rachel Rahib
Petrogenesis Of Enriched And Intermediate Poikilitic Shergottites: From Magmatic Source To Emplacement, Rachel Rahib
UNLV Theses, Dissertations, Professional Papers, and Capstones
Poikilitic shergottites, making up >20% of martian meteorites, likely represent a significant composition of the martian crust, as intrusive gabbroic rocks. To further constrain petrogenetic relationships amongst enriched and intermediate poikilitic shergottites, we utilize bulk rock trace element compositions, mineral major element compositions, phosphorus maps of olivine grains, oxygen fugacity (ƒO2) values, subsolidus equilibration temperatures, and quantitative textural analyses, of the most comprehensive suite of poikilitic shergottites yet (11 samples), including three newly recovered samples (Northwest Africa [NWA] 11065, NWA 11043, NWA 10961). Although petrographically light rare earth element (LREE) enriched and intermediate poikilitic shergottites are similar, distinct LREE abundances …
Prokaryotic Diversity And Aqueous Geochemistry Of Subsurface Environments Of The Death Valley Regional Flow System, Joshua David Sackett
Prokaryotic Diversity And Aqueous Geochemistry Of Subsurface Environments Of The Death Valley Regional Flow System, Joshua David Sackett
UNLV Theses, Dissertations, Professional Papers, and Capstones
This dissertation summarizes over four years of effort towards the completion of a Ph.D. in Biological Sciences. The work presented in this document covers a broad range of topics, but a central unifying theme is prokaryotic life in the continental subsurface. The work presented in each chapter relied heavily on cultivation-independent methods for assessing prokaryotic communities, including prokaryotic community structure reconstruction from high-throughput sequencing of 16S rRNA gene libraries and single-cell genome analysis of novel uncultivated bacteria.
Chapter 2 examines the aqueous geochemistry and prokaryotic diversity of Devils Hole, a cavernous limnocrene and sole natural habitat for the critically endangered …
Monitoring The Impact Of Groundwater Pumping On Infrastructure Using Geographic Information System (Gis) And Persistent Scatterer Interferometry (Psi), Kirsten Deprekel, El Hachemi Bouali, Thomas Oommen
Monitoring The Impact Of Groundwater Pumping On Infrastructure Using Geographic Information System (Gis) And Persistent Scatterer Interferometry (Psi), Kirsten Deprekel, El Hachemi Bouali, Thomas Oommen
Department of Geological and Mining Engineering and Sciences Publications
Transportation infrastructure is critical for the advancement of society. Bridges are vital for an efficient transportation network. Bridges across the world undergo variable deformation/displacement due to the Earth’s dynamic processes. This displacement is caused by ground motion, which occurs from many natural and anthropogenic events. Events causing deformation include temperature fluctuation, subsidence, landslides, earthquakes, water/sea level variation, subsurface resource extraction, etc. Continual deformation may cause bridge failure, putting civilians at risk, if not managed properly. Monitoring bridge displacement, large and small, provides evidence of the state and health of the bridge. Traditionally, bridge monitoring has been executed through on-site surveys. …
Mercury In Big Cypress Bayou And Caddo Lake Watersheds In Marion And Harrison Counties Texas, Joseph Watkins
Mercury In Big Cypress Bayou And Caddo Lake Watersheds In Marion And Harrison Counties Texas, Joseph Watkins
Electronic Theses and Dissertations
Caddo Lake has been included on the Texas Commission on Environmental Quality 303(d) list for impairment due to mercury (Hg) content since 1996. One of the primary tributaries, Big Cypress Bayou, flows across Eocene-aged rocks and sediments associated with the Wilcox Group; the Wilcox is of interest because it contains lignite coal, which has a direct link to mercury. Previous research has focused on dry deposition from fossil fuel combustion as the primary source of mercury but has not addressed the potential watershed contribution to mercury concentrations in Caddo Lake.
Big Cypress Bayou flows through Harrison and Marion counties in …
Delineation Of Karst Potential Using Lidar And Gis Analyses, Fort Hood Military Installation, Texas, Colby Reece
Delineation Of Karst Potential Using Lidar And Gis Analyses, Fort Hood Military Installation, Texas, Colby Reece
Electronic Theses and Dissertations
ABSTRACT
Traditional karst surveys require extensive field investigations to completely characterize large areas. They are often time-consuming, requiring up to several years to collect and categorize data. Bias is given to areas that are most easily accessible and false negatives are common. The implementation of geographic information systems (GIS) has aided in the aggregation and standardization of karst data; however, these systems have also been used to develop terrain models that allow the user to remotely delineate sinkholes and other surficial features. The Fort Hood Military Installation is a karst landscape that has been altered significantly for use in military …
Mineralogy, Petrology, And Geochemistry Of The Unique Silica-Rich Ungrouped Achondrite Northwest Africa 11575, Mya Ann Habermann
Mineralogy, Petrology, And Geochemistry Of The Unique Silica-Rich Ungrouped Achondrite Northwest Africa 11575, Mya Ann Habermann
Earth and Planetary Sciences ETDs
We report here on a unique, newly discovered, silica-rich ungrouped achondrite Northwest Africa 11575 (NWA 11575). NWA 11575 is one of four known silica-rich ungrouped achondrites, presenting evidence for igneous processes resulting in evolved compositions early in the history of the solar system. It is unique from the other silica-rich ungrouped achondrites in that it has pyroxene compositional trends matching those of lunar samples and martian meteorites; contains quartz and potassium feldspar; and contains oxygen, hydrogen, and chromium isotopes that are similar to those of LL chondrites. Together, these four silica-rich ungrouped achondrites provide evidence for evolved compositions resulting from …
Insights Into Fluid-Rock Interactions On The Cv3 Carbonaceous Chondrite Asteroid: The Complex Record In The Allende-Like Cv3 Chondrite, Nwa 2364., Jessica Marie Johnson
Insights Into Fluid-Rock Interactions On The Cv3 Carbonaceous Chondrite Asteroid: The Complex Record In The Allende-Like Cv3 Chondrite, Nwa 2364., Jessica Marie Johnson
Earth and Planetary Sciences ETDs
The two subgroups of the CV3 chondrites, oxidized and reduced, contain primitive solar system materials that provide many insights into early solar system processes. Both subgroups record significant evidence of secondary alteration that has modified their primary characteristics. In this work, we have studied the petrography, mineralogy, and oxygen isotopic composition of the NWA 2364 CV3OxA chondrite and a large lithic inclusion using SEM, electron microprobe, FIB/TEM, and laser fluorination oxygen isotope analyses in order to characterize their alteration histories in detail. The NWA 2364 host and lithic inclusion consist of chondrules, Calcium-Aluminum-rich Inclusions (CAIs), and fine-grained matrix. In …
The Ages2 (Awards For Geochronology Student Research 2) Program: Supporting Community Geochronology Needs And Interdisciplinary Science, Rebecca M. Flowers, J. Ramón Arrowsmith, Vicki Mcconnell, James R. Metcalf, Tammy M. Rittenour, Blair Schoene
The Ages2 (Awards For Geochronology Student Research 2) Program: Supporting Community Geochronology Needs And Interdisciplinary Science, Rebecca M. Flowers, J. Ramón Arrowsmith, Vicki Mcconnell, James R. Metcalf, Tammy M. Rittenour, Blair Schoene
Geosciences Faculty Publications
Geochronology is essential in the geosciences. It is used to resolve the durations and rates of earth processes, as well as test causative relationships among events. Such data are increasingly required to conduct cutting-edge, transformative, earth-science research. The growing need for geochronology is accompanied by strong demand to enhance the ability of labs to meet this pressure and to increase community awareness of how these data are produced and interpreted. For example, a 2015 National Science Foundation (NSF) report on opportunities and challenges for U.S. geochronology research noted: "While there has never been a time when users have had greater …
Widespread, Prolonged Microbial Limestone Deposition And Large, Rapid Sulfur Isotope Excursions: A New Perspective On The Early Triassic From The Western U.S., Brad M. Jeffrey
Earth and Planetary Sciences ETDs
The Early Triassic records a ~5 My period of marine biological recovery following the end-Permian mass extinction (EPME, ~252 My). Global oceans were characterized by warm sea-surface temperatures (SSTs), widespread anoxia, and major perturbations to the carbon cycle, the collective result of repeated massive Siberian Traps eruptions and associated global climate feedbacks. Globally widespread microbial deposits (stromatolites, thrombolites) developed in shallow marine environments. Several marine isotope records (C, O, S, U) indicate repeated, large-magnitude shifts related to paleoceanographic events during the recovery of marine ecosystems following the EPME.
Chapter 1 describes and interprets a widespread (~400 km along strike) Smithian …
Designing A Protected Area To Safeguard Imperiled Species From Urbanization, Stephanie S. Romanach, Brad Stith, Fred A. Johnson
Designing A Protected Area To Safeguard Imperiled Species From Urbanization, Stephanie S. Romanach, Brad Stith, Fred A. Johnson
United States Geological Survey: Staff Publications
Reserve design is a process that can address ecological, social, and political factors to identify parcels of land needed to sustain wildlife populations and other natural resources. Acquisition of parcels for a large terrestrial reserve is difficult because it typically occurs over a long timeframe and thus invokes consideration of future conditions such as climate and urbanization changes. In central Florida, the U.S. government has authorized a new protected area, the Everglades Headwaters National Wildlife Refuge. The new refuge will host important threatened and endangered species and habitats, and will be located to allow for species adaptation from climate change …
Assessing Ground Penetrating Radar's Ability To Image Subsurface Characteristics Of Icy Debris Fans In Alaska And New Zealand, Robert W. Jacob, Jeffrey M. Trop, R. Craig Kochel
Assessing Ground Penetrating Radar's Ability To Image Subsurface Characteristics Of Icy Debris Fans In Alaska And New Zealand, Robert W. Jacob, Jeffrey M. Trop, R. Craig Kochel
Faculty Journal Articles
Icy debris fans have recently been described as fan shaped depositional landforms associated with (or formed during) deglaciation, however, the subsurface characteristics remain essentially undocumented. We used ground penetrating radar (GPR) to non-invasively investigate the subsurface characteristics of icy debris fans (IDFs) at McCarthy Glacier, Alaska, USA and at La Perouse Glacier, South Island of New Zealand. IDFs are largely unexplored paraglacial landforms in deglaciating alpine regions at the mouths of bedrock catchments between valley glaciers and icecaps. IDFs receive deposits of mainly ice and minor lithic material through different mass-flow processes, chiefly ice avalanche and to a lesser extent …
Discovery Of Paleotsunami Deposits Along Eastern Sunda Arc: Potential For Megathrust Earthquakes In Bali, Hanif Ibadurrahman Sulaeman
Discovery Of Paleotsunami Deposits Along Eastern Sunda Arc: Potential For Megathrust Earthquakes In Bali, Hanif Ibadurrahman Sulaeman
Theses and Dissertations
Several laterally extensive candidate tsunami deposits are preserved along coastlines facing the eastern Java Trench, indicating it has experienced mega-thrust earthquakes in the past. We investigated 37 coastal sites in Bali, Lombok, Sumba and Timor islands, many of which preserve course sand and pebble layers that overlie sharp basal contacts with scour marks into the mud, fine upward in grain size, and have bimodal grain size distributions. Other unique features are the common occurrence of marine fossils and concentrations of heavy minerals. The occurrence of these high-energy deposits interlayered with clay-rich units indicates the coarse clastics are anomalous because they …
Improving Sinkhole Mapping Using Lidar Data And Locating Sinkhole Hotspots In Johnson City, Tn, Kingsley Fasesin
Improving Sinkhole Mapping Using Lidar Data And Locating Sinkhole Hotspots In Johnson City, Tn, Kingsley Fasesin
Electronic Theses and Dissertations
Predicting infrastructure damage and economic impact of sinkholes requires high accuracy mapping distribution and development. The study mapped sinkholes and sinkhole hotpsots in Johnson City, TN using LiDAR-derived Digital Elevation Model (DEM) and a database of known sinkholes which were matched to LiDAR-derived depressions. For all matched depressions (n = 404), three metrics were calculated: circularity index, ratio of length to width of the Minimum Bounding Rectangle (MBR) and percent coverage of the MBR by the depression, and 3,634 new sinkholes were identified. Newly developed hotspots were identified in north Johnson City and other areas in the south near the …
Subsurface Analysis Of Mississippian Tripolitic Chert In Northwest Arkansas, Thomas Jason Liner
Subsurface Analysis Of Mississippian Tripolitic Chert In Northwest Arkansas, Thomas Jason Liner
Graduate Theses and Dissertations
Over the past 70 years the Mississippian strata of Northwest Arkansas have been studied in great detail. The study area is located on the escarpment between the Boston Mountains Plateau and the Springfield Plateau where a surface occurrence of Mississippian age rock allows for access to outcrops in close proximity to gas wells that encounter subsurface Mississippian strata. Many outcrops found in Northwest Arkansas expose Lower Mississippian (Kinderhookian-Osagean) strata that represent a full third order transgressive/regressive sequence that is unconformity bounded. These Mississippian outcrops are commonly treated as surface analogs to the Mississippi Lime Play in North Central Oklahoma. This …
Subsurface Stratigraphic Interpretation Of The Lower Atoka Formation, Northern Arkoma Basin, Arkansas, William Stephen Denham
Subsurface Stratigraphic Interpretation Of The Lower Atoka Formation, Northern Arkoma Basin, Arkansas, William Stephen Denham
Graduate Theses and Dissertations
The Arkoma Basin is a Carboniferous peripheral foreland basin creating a structural depression covering an approximate area of 33,800 miles2 that extends through east-central Oklahoma and west-central Arkansas. The entire basin fill includes Pre-Mississippian carbonate shelf deposits, Mississippian marine carbonates and black shales, and Pennsylvanian mixed carbonated/clastic and shore zone/deltaic deposits. The Lower Atoka formation (Pennsylvanian) occurs in outcrop along the southern Boston Mountain Plateau in northern Arkansas and extends into the subsurface of the Arkoma Basin over an area of 2,300 miles2. The Lower Atoka ranges from 600 to 1500 feet in thickness and represents a cyclic succession of …
Assessing Land Deformation And Sea Encroachment In The Nile Delta: A Radar Interferometric And Modeling Approach, Esayas Gebrekidan Gebremichael
Assessing Land Deformation And Sea Encroachment In The Nile Delta: A Radar Interferometric And Modeling Approach, Esayas Gebrekidan Gebremichael
Dissertations
Many of the deltas of the world are experiencing land deformation, subsidence or uplift of landmass, due to natural or anthropogenic causes, or a combination of both processes and causes. These deltaic settings are densely populated and border some of our world’s largest water bodies (oceans and seas). The land deformation, especially the subsidence component, when combined with the climate change-induced sea level rise, coastal erosion, and other anthropogenic drivers, will undoubtedly impact the population and economy of coastal areas of deltas. For the Nile Delta of Egypt, the land deformation processes and the factors that control the deformation processes …
Evaluating Stable Isotope And Geochronologic Techniques For Paleoclimate Reconstruction: Case Study Of The Santa Cruz Formation, Argentina, Robin B. Trayler
Evaluating Stable Isotope And Geochronologic Techniques For Paleoclimate Reconstruction: Case Study Of The Santa Cruz Formation, Argentina, Robin B. Trayler
Boise State University Theses and Dissertations
Stable isotope analysis has become the method of choice for many studies investigating the paleoecology and paleoclimate of fossil mammal faunas. While organic tissues (collagen, keratins, proteins) persist for < 105 years highly mineralized tooth enamel is resistant to alteration and degradation and faithfully preserves its isotopic composition for millions (> 106) years. Reconstructing past climates from these records relies on both understanding both micro-scale mechanisms of isotope incorporation into individual teeth, and macro-scale changes in isotope compositions over hundreds of thousands or millions of years. In this dissertation I address three questions.
First, how does the geometry and …
Exploring Potential Water-Ice Occurrence On Asteroid 4 Vesta Using Orbital Radar Observations By The Dawn Mission, Elizabeth M. Palmer
Exploring Potential Water-Ice Occurrence On Asteroid 4 Vesta Using Orbital Radar Observations By The Dawn Mission, Elizabeth M. Palmer
Dissertations
Airless, differentiated planetesimals in the inner solar system were presumed to have been depleted of most of their initial volatile content during formation. However, water-ice has been discovered at the lunar poles (Li et al., 2018), is inferred to exist in polar craters on Mercury (e.g., Butler, Slade & Muhleman, 1993, and suggested to survive beneath the dusty regolith of objects in the main asteroid belt if buried at sufficient depths—at least one meter for small-bodies in the outer main-belt (Schorghofer, 2008). Hence, the study of volatile occurrence, past or present, on airless, desiccated small-bodies provides insights into the timing, …
New Ca-Id-Tims Detrital Zircon Constraints On Middle Neoproterozoic Sedimentary Successions, Southwestern United States, Abigail R. Bullard
New Ca-Id-Tims Detrital Zircon Constraints On Middle Neoproterozoic Sedimentary Successions, Southwestern United States, Abigail R. Bullard
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Three related sedimentary successions located in Arizona, Utah, and California were deposited in basins on proto-North America during the early rifting of Rodinia (~780 Mya). Previous detrital zircon U-Pb maximum ages for the units are inexact, making it difficult to piece together what happened at this point in Earth history.
We report better maximum age constraints on these units obtained by subjecting detrital zircons to high-precision CA-ID-TIMS analysis, which provide more exact 206Pb/238U ages. These new data significantly improve the precision for the base of the ChUMP units, with an average age of 775.63 ± 0.27 Ma …
Compositional And Thermodynamic Variability In A Stratified Magma Chamber: Evidence From The Green Tuff Ignimbrite (Pantelleria, Italy)., Katarzyna M. Liszewska, John C. White, Ray Macdonald, Bogusław Bagiński
Compositional And Thermodynamic Variability In A Stratified Magma Chamber: Evidence From The Green Tuff Ignimbrite (Pantelleria, Italy)., Katarzyna M. Liszewska, John C. White, Ray Macdonald, Bogusław Bagiński
EKU Faculty and Staff Scholarship
The Green Tuff Ignimbrite, Pantelleria, is compositionally zoned from pantellerite at the base to comenditic trachyte at the top, the variation apparently representing an inverted vertical zonation in the pre-eruptive reservoir. The main phenocryst assemblages are alkali feldspar + olivine + clinopyroxene + ilmenite + apatite in the trachytes and alkali feldspar + aenigmatite + clinopyroxene + quartz in the rhyolites. Thermodynamic modelling indicates that the temperature range was ~900–700°C, fO2 FMQ –1.5 to FMQ –0.5 (where FMQ is fayalite–magnetite–quartz buffer) and aSiO2 (relative to quartz saturation) 0.74–1.00. Melt water contents ranged from ~1wt % in the trachytes to ~4wt …
Holocene Formation And Evolution Of Horn Island, Mississippi, Usa, Nina Gal
Holocene Formation And Evolution Of Horn Island, Mississippi, Usa, Nina Gal
Master's Theses
Horn Island, one of the most stable barriers along the Mississippi-Alabama chain, provides critical habitat, helps regulate estuarine conditions in the Mississippi Sound, and reduces wave energy and storm surge for the mainland. This study integrates 2,200 km of high-resolution geophysics, 35 sediment cores, and 15 radiocarbon ages to better understand the formation and evolution of the island in response to sea-level rise, storms, and antecedent geology. The Biloxi and Pascagoula incised valleys converge at Horn Island and have played a profound role in the evolution of the system. Within the incised valleys, numerous shallow paleochannels between 4 and 9 …
Physical And Chemical Controls On Suffosion Development In Gypsic Soil, Culberson County, Texas, Jonah Morris
Physical And Chemical Controls On Suffosion Development In Gypsic Soil, Culberson County, Texas, Jonah Morris
Electronic Theses and Dissertations
In the Gypsum Plain, suffosion processes have encouraged road failure through dissolution and transport of gypsic soils; however, no prior research has been conducted within the Delaware Basin in regard to these processes. These phenomena were evaluated in both field and laboratory settings in order to assess the parameters of suffosion development associated with Ranch to Market (RM) 652 in Culberson County, Texas, where infrastructure extends across Castile and Rustler strata. Field studies simulated surficial ponding in various gypsic soils and correlated suffosion potential with soil composition and thickness. Soluble fractions of gypsic soils were delineated through geochemical analyses, further …
Predicted Deepwater Bathymetry From Satellite Altimetry: Non-Fourier Transform Alternatives, Maxsimo Salazar
Predicted Deepwater Bathymetry From Satellite Altimetry: Non-Fourier Transform Alternatives, Maxsimo Salazar
Dissertations
Robert Parker (1972) demonstrated the effectiveness of Fourier Transforms (FT) to compute gravitational potential anomalies caused by uneven, non-uniform layers of material. This important calculation relates the gravitational potential anomaly to sea-floor topography. As outlined by Sandwell and Smith (1997), a six-step procedure, utilizing the FT, then demonstrated how satellite altimetry measurements of marine geoid height are inverted into seafloor topography. However, FTs are not local in space and produce Gibb’s phenomenon around discontinuities. Seafloor features exhibit spatial locality and features such as seamounts and ridges often have sharp inclines. Initial tests compared the windowed-FT to wavelets in reconstruction of …
Hydrogeologic Framework Studies Of Portions Of The Niobrara River, Douglas R. Hallum, Steven S. Sibray, Leslie M. Howard
Hydrogeologic Framework Studies Of Portions Of The Niobrara River, Douglas R. Hallum, Steven S. Sibray, Leslie M. Howard
Conservation and Survey Division: Faculty and Staff Publications
The Nebraska Department of Natural Resources (NeDNR) and Upper Niobrara-White Natural Resources District (UNWNRD) expressed interest in improving understanding and their ability to effectively manage water resources in and around a particular reach of the Niobrara River. Aquifer-thickness contours mapped by the Conservation and Survey Division (CSD) indicate that the principle aquifer has zero thickness in this area. Additionally, the statewide geologic bedrock map produced by CSD shows non-aquifer strata of the White River Group along the same reach, and this setting is consistent with the designation of an “aquifer absent area,” as in the present document. Water-management policy development …